正弦波过零畸变求助！

现在使用F28027做单相逆变器，使用PI控制器，详细程序见下面！
现在遇到逆变输出的正弦波过零附近出现畸变，电压和电流波形见附图

// -----------------------------------------------------------
// PIE Group 1 - MUXed into CPU INT1
// -----------------------------------------------------------
// INT1.1  Can also be ISR for INT10.1 when enabled
interrupt void ADCINT1_ISR(void)  
{
 signed int Width_Pulse=0;
 signed int temp=0;
 if(++sym_clock==400)
   {
    sym_clock=0;
    Vol_Peak_Shadow=Vol_Peak;
    Width_Compensate=-Width_Sum/400;
    if((sym_state==0)&&((Width_Compensate>300)||(Width_Compensate<-300)))
      {
       EALLOW;
       //GpioDataRegs.GPACLEAR.bit.GPIO5  = 1;
       sym_state=3;
       EDIS;
       }
    }
   
 
 if(sym_clock>=200)
   {
    Vol_Ref=-SinTable[sym_clock-200]*Vol_Peak_Shadow;
    }
 else  
   {
    Vol_Ref=SinTable[sym_clock]*Vol_Peak_Shadow;
    }
 temp=AdcResult.ADCRESULT3>>2;  
 Vol_Feed=(float)(temp-517)*SCALE_VOLTAGE;
 //Vol_Feed=(float)(temp-Offset_Adcb3)*SCALE_VOLTAGE;
 //Vol_Feed=(float)(660-Offset_Adcb3)*SCALE_VOLTAGE;
   
 Vol_Err    =Vol_Ref-Vol_Feed;    
 Vol_Out    =Vol_Err*0.12365;//-Vol_Err_Last*0.012365*0.7334+Vol_Out;

 
 
 Vol_Err_Last=Vol_Err;
 
 Width_Pulse=(int)(Vol_Out/330*1500);
 
 Width_Pulse=Width_Pulse+Width_Compensate;  
 
 if(Width_Pulse>3)
   {
    if(Width_Pulse>=1472)
      {
       Width_Sum=Width_Sum+1500;
       Width_Pulse=0;
       }
    else
      {
       Width_Sum=Width_Sum+Width_Pulse;
       Width_Pulse=1475-Width_Pulse;
       }
    EALLOW;
    EPwm1Regs.CMPA.half.CMPA      =Width_Pulse;
    EPwm2Regs.CMPA.half.CMPA      =1600;
    EDIS;
    }
 else
   {
    if(Width_Pulse<-3)
      {
       Width_Pulse=-Width_Pulse;
       if(Width_Pulse>=1472)
         {
          Width_Sum=Width_Sum-1500; 
          Width_Pulse=0;
          }
       else
         {
          Width_Sum=Width_Sum-Width_Pulse;
          Width_Pulse=1475-Width_Pulse;
          }
       EALLOW; 
       EPwm1Regs.CMPA.half.CMPA      =1600;
       EPwm2Regs.CMPA.half.CMPA      =Width_Pulse;
       EDIS;
       }
    else
      {
       EALLOW;
       EPwm1Regs.CMPA.half.CMPA      =1600;
       EPwm2Regs.CMPA.half.CMPA      =1600;
       EDIS;
       }
    }
 sym_tick=1;

 Vol_Square_Sum=Vol_Square_Sum+Vol_Feed*Vol_Feed;
 if(sym_clock==200)
 {
  Vol_Sqr_Sum_Shw=Vol_Square_Sum;
  Vol_Square_Sum=0;
  sym_RMS=1;
  }
 
 EALLOW;
 AdcRegs.ADCINTFLGCLR.bit.ADCINT1 = 1;       //Clear ADCINT1 flag reinitialize for next SOC
 AdcRegs.ADCINTOVFCLR.bit.ADCINT1 = 1;
 PieCtrlRegs.PIEACK.bit.ACK10     = 1;        //Acknowledge interrupt to PIE
 EDIS;
}